Scientists Discover Sawfish Escape Extinction Through "Virgin Births"

An anonymous reader writes: The first known virgin births in smalltooth sawfish have been documented in the wild. Researchers from the Florida Fish and Wildlife Conservation Commission used DNA to show that three percent of a Florida sawfish population was created by female-only reproduction. Dr Warren Booth, an evolutionary biologist at the University of Tulsa, who previously discovered an instance of parthenogenesis in snakes, said: "This is basically a very extreme form of inbreeding. Most people think of inbreeding as bad, but it could be helpful in purging deleterious mutations from a population." The findings were published in the journal Current Biology.

Comments

inbreeding beneficial?

[binarstu]

From TFA summary:

Dr Warren Booth, an evolutionary biologist at the University of Tulsa, who previously discovered an instance of parthenogenesis in snakes, said: "This is basically a very extreme form of inbreeding. Most people think of inbreeding as bad, but it could be helpful in purging deleterious mutations from a population."

Most people think of inbreeding as bad, because it almost always is bad. Inbreeding depression is a very well documented, and well understood, phenomenon that can increase the extinction risk of critically endangered species. The idea that inbreeding can somehow be "helpful in purging deleterious mutations" has been discussed before, but a recent study found that even if small (e.g., endangered) populations are actively managed to control both inbreeding and outbreeding, the negative effects of inbreeding depression generally outweigh the benefits of removing harmful alleles. And that is a best case scenario, with reproduction carefully controlled to produce an optimal genetic outcome, which obviously does not happen naturally.

For these sawfish, asexual reproduction is most likely a desperation strategy used when the population has gotten so small that it is difficult or impossible to find mates. It is extremely unlikely that it will somehow improve the population's genetic fitness; more likely, it will lead to further decreases in genetic diversity and a corresponding loss of overall fitness.

Re:inbreeding beneficial?

[Trailer Trash]

For these sawfish, asexual reproduction is most likely a desperation strategy used when the population has gotten so small that it is difficult or impossible to find mates. It is extremely unlikely that it will somehow improve the population's genetic fitness; more likely, it will lead to further decreases in genetic diversity and a corresponding loss of overall fitness.

I would point out furthermore that inbreeding and asexual reproduction have nothing to do with each other. It's unrelated. The problem with inbreeding is that you can get two copies of a single chromosome quite easily, and rare genetic diseases that appear only when the same gene is present on both chromosomes in a pair suddenly start popping up more often.

That's not an issue with asexual reproduction. It might at some point become an issue if the genetic diversity of the group becomes lesser, but that would be down the road somewhere.